Arthroscopic bone transplanting procedure, and medical instruments useful therein

ABSTRACT

Described is an arthroscopic bone transplanting procedure for transplanting a section of a first bone to a second bone. The described procedure is particularly useful for the treatment an anterior shoulder instability, where the first bone is the coracoid and the second bone is the glenoid. Also described is a kit of medical instruments particularly useful in such a procedure.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.12/375,422 filed on Nov. 6, 2009, which is a National Phase of PCTPatent Application No. PCT/IL2007/000952 having International filingdate of Jul. 30, 2007, which claims the benefit of priority of U.S.Provisional Patent Application No. 60/834,173 filed on Jul. 31, 2006.The contents of the above Applications are all incorporated herein byreference.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an arthroscopic bone transplantingprocedure and to medical instruments useful in such a procedure as maybe supplied in the form of a kit. The invention is particularly usefulin the treatment of an anterior shoulder instability, where a section ofthe coracoid is transplanted to the glenoid, and is therefore describedbelow with respect to said transplant.

The range of movements the human shoulder can make far exceeds any otherjoint in the body. The shoulder joint is a ball and socket joint,similar to the hip; however, the socket of the shoulder joint isextremely shallow, and thus inherently unstable. Muscles and tendonsserve to keep the bones in approximation. In addition, in order tocompensate for the shallow socket, the shoulder joint has a cuff offibrous cartilage called a labrum that forms a cup for the head of thearm bone (humerus) to move within. This cuff of cartilage makes theshoulder joint much more stable, yet allows for a very wide range ofmovement. When the labrum of the shoulder joint is damaged, thestability of the shoulder joint is compromised, leading to subluxationand dislocation of the joint. Recurrent dislocations may cause damage tothe bones of the joint—the humeral head and the glenoid. In particular,damage to the anterior-inferior part of the glenoid will cause adecrease in the area of contact with the humeral head.

When bone deficiencies associated with anterior shoulder instability arepresent, the prognostic factors for the success of soft tissue repairare poor. Current standards of success are predicated on the restorationof motion and strength and the return to full functional activities,including competitive athletics. Reestablishment of anterior shoulderstability requires the recognition and the treatment of osseous defects.

Several surgical procedures have been described for the management ofosseous deficiencies in association with anterior shoulder instability,involving the transplantation of a portion of the coracoid process tothe anterior-inferior section of the glenoid. The procedure described byLatarjet in 1954 involves the transplantation of a large section of thecoracoid together with the conjoined tendon attached to it to reinforcethe glenoid fossa and create an antero-inferior musculotendinous sling.The procedure has been performed since its disclosure with positiveresults as an open surgical intervention.

However, up to the present, no minimally invasive technique forperforming it has been developed.

OBJECTS AND BRIEF SUMMARY OF THE PRESENT INVENTION

An object of the present invention is to provide an arthroscopic bonetransplanting procedure which is particularly useful in the treatment ofanterior shoulder instability, but may be used in other proceduresinvolving implanting of a section of a first bone to a second bone. Afurther object of the invention is to provide instruments, which may besupplied in kit form, particularly useful in such an arthroscopicprocedure.

According to one aspect of the present invention, there is provided anarthroscopic procedure for transplanting a section of a first bone to asecond bone, comprising the following steps: (a) making small incisionsto open portals for the introduction of medical instruments; (b)drilling a threaded bore in said section of said first bone; (c)attaching a first cannula to said section of said first bone; (d)separating said section from said first bone; (e) positioning saidseparated section of said first bone on said second bone; (f) replacingsaid first cannula by a second cannula attached to said separated bonesection by a cannulated device; (g) introducing a guide wire through thecannulated device; (h) removing the cannulated device; (i) drilling abore into the second bone by a cannulated drill guided by said guidewire; (j) removing the guide wire; (k) and applying a bone screw throughsaid bore in said separated section of the first bone and said bore insaid second bone.

The preferred embodiment of the invention described below isparticularly useful for the treatment of anterior shoulder instability,or other disorders where it is desired to use at least two bone screwsfor attaching a section of a first bone to a second bone. When such aprocedure is used, in step (b), two threaded bores at a fixed distancefrom each other are drilled in said section of the first bone; in step(c), the first cannula is a T-handle cannula and is attached in saidfirst bore by sutures or flexible wires; in step (f), the second cannulais a double cannula and is attached to said section of the first bone bytwo cannulated devices; in step (g), two guide wires are introducedthrough the two cannulated devices, which cannulated devices are thenremoved in step (h); in step (i), two bores are drilled into the secondbone by a cannulated drill guided by said guide wires; in step (j), thetwo guide wires are removed; and in step (k), two bone screws areapplied through the two bones in the separated section of the firstbone, and the two bores in the second bone.

Other aspects of the invention involve the construction of medicalinstruments, which may be supplied in a kit, particularly useful for theabove-described bone transplanting procedures.

Further features of the invention will be apparent from the descriptionbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is herein described below, the reference to theaccompanying drawings, wherein:

FIG. 1 a is a schematic drawing of the gleno-humeral joint in theshoulder;

FIG. 1 b is a schematic lateral view illustrating damage to the glenoidfossa;

FIG. 2 a is a schematic anterior view of the bone reconstruction;

FIG. 2 b is a transverse section through the reconstructed joint, and

FIGS. 3-20 illustrate various medical instruments, which may be suppliedin kit form, particularly useful in an arthroscopic bone transplantingprocedure for reconstructing the shoulder joint in accordance with thepresent invention, in which:

FIG. 3 shows a standard Kirschner wire;

FIG. 4 is a cannulated bone drill;

FIG. 5 shows a drill guide for drilling a second bore at apre-determined distance from a first bore;

FIG. 6 is a thread tapping tool;

FIG. 7 a is a suture loader;

FIG. 7 b is a suture retriever;

FIG. 8 shows a flexible wire;

FIG. 9 is a cannula with a T-handle;

FIG. 10 shows osteotomes, straight and curved;

FIG. 11 is a cannulator for a double cannula;

FIG. 12 is a double cannula;

FIG. 13 shows a suture hook;

FIG. 14 shows a cannulated device

FIG. 15 is a cannulated device driver;

FIG. 16 is a cannulated spike;

FIGS. 17 a and 17 b are side and top views, respectively, of a clampingdevice for holding a transplanted bone section to the receiving site;

FIG. 18 shows cannulated bone drills;

FIG. 19 is a cannulated bone screw;

FIG. 20 is a screwdriver with a long cannulated shaft for the bonescrews; and

FIG. 21 is a flow diagram illustrating a preferred arthroscopicprocedure in accordance with the present invention.

THE CONSTRUCTION OF THE SHOULDER JOINT

FIG. 1 a illustrates the bones of the shoulder joint. The head 1 of theupper arm bone, the humerus 2, forms a ball-and-socket joint with theshallow glenoid cavity 3. The glenoid is the lateral part of theshoulder blade scapula 4. Two hook-like projections of the scapula seenoverhanging the glenoid are the acromion 5 and the coracoid process 6. Agroup of muscles collectively known as the Rotator Cuff originate on thescapula and insert on the humerus. These serve to stabilize the joint bykeeping the humeral head in contact with the glenoid cavity. Theclavicle 7 connects the acromion to the breastbone sternum. The glenoidlabrum 8, which is a flexible fibrous ligament, surrounds the glenoidrim enlarging its area of contact with the humerus. When dislocations inthe direction shown by the arrow occur, the anterior-inferior part ofthe labrum is torn away from the glenoid, causing instability of thejoint. Recurring dislocations may lead to osseous lesions.

FIG. 1 b illustrates the type of damage to the glenoid socket caused bysuch dislocations. The pear-shape of the intact glenoid is shown at “A”;while bone loss at the inferior, wider section “A”, caused by adislocation, is shown at “B” and results in an inverted pear shapenarrower lower section as shown at “C”. This causes a partial loss ofcontact with the humeral head.

FIGS. 2 a and 2 b illustrate a bone reconstruction in accordance withthe present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

The description below describes a kit of instruments, and the method oftheir use, for performing coracoid transfer (Latarjet procedure)arthroscopically. The kit consists of various instruments, includingdrills, drill guides, osteotomes, cannulae, suture manipulators, screws,screwdrivers and others, specific for the purpose of the methoddisclosed by the invention.

A Bone Transplantation Procedure and the Medical Instruments UsedTherein

The procedure consists of the following main steps:

-   -   Opening portals (small incisions); introducing the arthroscope        and instruments    -   Preparation of the coracoid and glenoid surfaces    -   Drilling and threading two holes in the coracoid at a fixed        distance    -   Passing sutures or flexible wires through the holes    -   Attaching the coracoid by sutures or flexible wires to a cannula    -   Separating the section of the coracoid to be transferred    -   Positioning the graft on the glenoid    -   Attaching a double cannula to the coracoid with a cannulated        device    -   Introducing K-wires through the cannulated device    -   Removing the cannulated device    -   Drilling into the glenoid with a cannulated drill over the        K-wires    -   Attaching the transplanted coracoid onto the glenoid with bone        screws    -   Removing the K-wires    -   Final fixing of the transplant (tightening the screws)    -   Removing the cannula.

In the reconstruction of the shoulder joint according to the presentinvention illustrated in FIGS. 2 a and 2 b, 20 indicates the glenoid, 21illustrates the coracoid graft implanted thereto by a pair of cannulateddevices 22 and 23, 24 indicates the humeral head, and 25 indicates theconjoined tendon.

FIG. 21 shows the above described procedure divided into the followingmain building blocks, including:

-   -   preparing the surfaces of the first and second bones (211),    -   separating a section of the first bone (212),    -   maneuvering the separated section of the first bone onto the        second bone (213), and    -   attaching the section of the first bone to the second bone        (215).        A Bone Transplantation Procedure and the Medical Instruments        Used Therein

FIGS. 3-20 illustrate the various medical instruments, preferablysupplied in kit form, for performing an arthroscopic bone transplantingprocedure in accordance with the present invention.

Portals (small incisions) are first made for introducing the arthroscopeand instruments and for preparing the coracoid and glenoid surfaces,leaving the conjoined tendon (shown in FIG. 2 b) attached to thecoracoid. Two threaded holes are drilled in the coracoid process, usingthe bone drill shown at 32 in FIG. 4 with a diameter of about 3 mm. AKirschner wire 31 (FIG. 3) is inserted at a safe distance from thelateral tip of the process for guiding the bone drill, and the firsthole is drilled. For placing the second hole, the drill is insertedthrough the drill guide shown at 33 in FIG. 5. A guide pin 33 a fixed atdistance “d” from the center of the drill nut 33 b ensures apredetermined distance of about 9 mm from the first hole. Both holes arethreaded now with the elongated tap shown at 34 in FIG. 6. Forsafeguarding the integrity of the transplant, inserts may be implantedin the holes.

Suture strands or flexible wires are now attached to the coracoidprocess for securing during separation by threading them through theholes. A suture loader 35, FIG. 7 a, and a suture retriever 36, in FIG.7 b are provided in the kit for manipulating the sutures. An alternativeflexible wire 37 is shown in FIG. 8. The sutures/wires are drawn outthrough the shaft of a T-handle cannula shown at 38 in FIG. 9 and arefixed at the proximal, handle section of the cannula for holding thecoracoid graft during separation and transfer to the receiving site.Osteotomes, such as those shown at 39 a, 39 b in FIG. 10, serve toseparate the lateral section of the coracoid. At least one osteotome isprovided in the kit.

Preparing for the transfer of the separated section of the coracoid, thesubscapularis muscle is dissected and split to allow for transferringthe T-handle cannula 38 with the coracoid transplant to theanterior-inferior, damaged section of the glenoid. The cannulator shownat 40 in FIG. 11 is used to dissect tissue and to free a passage to thereceiving site. A double cannula shown at 41 in FIG. 12 is insertedthrough the passage freed by the cannulator.

The two tubes “t” of the double cannula 41 are fixed, so that thedistance of their centerlines “d” is identical to that of the drillguide 33 in FIG. 5. Handle “h” attached to the tube is offset at anangle “a” relative to the axis of the tubes and is formed to provide afirm grip. Angle “a” should be of an order of 40 to 65 degrees to allowmaneuvering without obstructing the field of vision, and the length ofthe tubes measured from the handle should be about 150 mm. A window “w”is cut in each of the tubes near the distal end to enable observation ofthe interior of the two tubes, and the position of an instrumentintroduced into the tubes.

When the double cannula has been inserted to face the coracoidtransplant, the T-handle cannula 38 is released from the sutures/wiresattached to the graft and is withdrawn. Using a suture hook shown at 42in FIG. 13, the sutures/wires are drawn through the tubes of the doublecannula and an elongated cannulated holding device such as screws 43shown in FIG. 14 are inserted over them into the tubes of the cannula.The screws are driven into the coracoid using a suitable instrument,such as the screw driver shown at 44 in FIG. 15 until the coracoid isfirmly attached to the cannula. An alternative device for holding theseparated coracoid bone transplant to the double cannula is shown at 45in FIG. 16. The distal section of the spike in FIG. 16 is expandable tohold the device to the walls of the bores of the graft.

The sutures/wires holding the coracoid can now be removed. The exactpositioning on the glenoid may be assisted by using a suitableinstrument, such as the clamping device shown at 46 in FIGS. 17 a and 17b. Once the transplant is in the correct position on the glenoid,Kirschner wires (31, FIG. 3) are driven into the glenoid through thecannulated devices holding the coracoid. The devices are now removedusing the screwdriver 44, FIG. 15, or by releasing the spike 45.

The double cannula serves as a drill guide. With a cannulated drill 47a, FIG. 18, inserted over one of the Kirschner wires, a first hole isdrilled into the glenoid. Leaving the first drill in position, the otherdrill 47 b in FIG. 18, with the longer shaft, is used to drill a secondhole over the second Kirschner wire.

After removing the drills, cannulated bone screws 48, FIG. 19, areinserted over the K-wires into the coracoid graft and are screwedpart-way into the glenoid using the cannulated device driver with a longshaft 49, FIG. 20, for use with the cannulated bone screws.

The K-wires can now be pulled out and the optional bone clamping deviceis removed. The bone screws 48 are drawn tight and the double cannula iswithdrawn to conclude the procedure.

While the invention has been described with respect to a preferredembodiment, it will be appreciated that this is set forth merely forpurposes of example, and that many other variations, modifications andapplications of the invention may be made.

What is claimed is:
 1. A medical kit of instruments for transplanting a section of a first bone to a second bone, comprising: a double cannula having two tubes extending parallel to each other, the double cannula having a proximal end carrying a handle, and a distal end formed with a window in each of said tubes to enable observing the interiors of said tubes; a clamping device including a proximal end having a handle, a distal end formed with a hook engageable with the distal side of the second bone, and a displaceable finger piece carried by said proximal end of the clamping device for displacing said hook towards or away from said handle of the clamping device; and at least two elongated cannulated holding devices, each sized to fit within one of said two tubes of said double cannula and configured to engage said section of said first bone to firmly attach said bone section to said double cannula.
 2. The medical kit according to claim 1, wherein said elongated cannulated holding device is in the form of a screw.
 3. The medical kit according to claim 1, wherein said elongated cannulated device is in the form of a spike comprising an expandable distal section to hold said double cannula to walls of a bore within said bone section.
 4. The medical kit according to claim 1, wherein a lumen of said elongated cannulated device is sized to receive a suture or guide wire.
 5. The medical kit according to claim 1, wherein said handle at an angle of 40-65° relative to a longitudinal axis of said tubes.
 6. The medical kit according to claim 5, wherein a length of said tubes from said handle to a distal end ranges between 100-200 mm.
 7. The medical kit according to claim 1, wherein each of said tubes is sized to receive a cannulated drill insertable over a guide wire.
 8. The medical kit according to claim 7, wherein said drill has a diameter ranging between 2-5 mm.
 9. The medical kit according to claim 1, wherein said kit further comprises at least one osteotome for separating said section of said first bone.
 10. The medical kit according to claim 9, wherein said osteotome is straight.
 11. The medical kit according to claim 9, wherein said osteotome is curved.
 12. The medical kit according to claim 1, wherein said kit further comprises a cannulator for dissecting tissue and freeing a passage to the receiving site.
 13. The medical kit according to claim 1, wherein said kit further comprises two drills for producing two bores through said section of said first bone at a precise distance from each other, and wherein said double cannula serves as a drill guide by receiving two drills within said two tubes.
 14. The medical kit according to claim 13, wherein a distance between the axes of said tubes of said double cannula is fixed.
 15. The medical kit according to claim 1, wherein said handle is fixed to a shaft, and said hook is carried at the distal end of a rod which is displaceable within said shaft towards and away from said handle by said finger piece.
 16. The medical kit according to claim 15, wherein said clamping device includes a movable element configured on said handle and engageable with said finger piece to move same axially of said handle.
 17. The medical kit according to claim 16, wherein said movable element is a nut threaded on said handle, and said finger piece is movable by threading said nut in one or the other direction with respect to said handle. 